As usual, I completely disagree regarding the comments along the lines of "just let the Nav take care of your charge". This assumes a mature Supercharger network everywhere I go, and this is absolutely not the case where I drive. Even when I was in the US, my destinations were 100% decided by Superchargers,
I don't decide where I get to travel. Besides that, my experience with its projections in Winter were consistently terrible (summer is accurate though) to the point that the car
would have stranded me if I listened to it (CHAdeMO stops were necessary and thankfully available). I do look forward to the day this is true though, perhaps starting with adding CHAdeMO/CCS to the maps for all countries (and giving North America a CCS adapter!).
Could you provide more detail on what the differences are? Source references also.
Thanks.
This may be a poor reflection on my character, but reading "Source references also" made me really not want to reply. Sorry. Every time I see this, the poster is generally only happy with something like a Tesla engineer's quote or something like that, which I clearly do not have. My fault, but it's also not super on topic with the thread (kind of, explaining how they cannot be compared for degradation).
But in the off chance I'm just being pessimistic and this is a benign request for information, have some stuff!:
- RE: Control Software is different
- This is a design necessity due to the hardware being very different, plus their opportunity to integrate things they've learned from S/X.
- Temperature management is a good observable example of this (noting their temperature management mechanisms are completely different). Preconditioning for Supercharging in a Model 3 heats the battery much more than an S/X, and an S/X will cool the battery much sooner in the charge process (whereas the 3 may not even reach the point of active cooling). This is even despite the fact that the S/X packs have less power going into them than 3/Y. To be fair, this may have changed on more recent S/X, I don't have data on this but have no reason to expect this is true given their designs are still completely different.
- RE: BMS is different
- See below these points, but also the previous point.
- I'll show this a simple way. Looking up pictures can show you they're very different. The Model 3 has 1 large board per series module (of which there are only 4). The Model S also seems to have one smaller board per module, but there are many more modules (at least 14). Even just a visual inspection of these boards shows they're very different, and the ones in the 3 seems to have a redundant microcontroller setup (safety? backup?).
- RE: Allowed cell voltages are different
- A few different ways to observe this.
- For one, you can infer the max voltage from CHAdeMO stations that display the input voltage. For example, I've now seen one at 403V. We know from information that's gone public that there are 96 bricks of cells in series. This means 4.198V/cell, so they're probably going right up to 4.2V/cell. Older S/X owners on these forums report lower max voltages than this, though this may be due to ageing and protection of the battery.
- The bottom end is harder to tell. Those who have scanned OBD-II data* have noted the cell voltages can go as low as 2.5V/cell. I can't find the references anymore, but the Model S/X packs appear to have a much higher minimum voltage threshold.
- RE: The way range is reported is different.
- This is mostly a result of the software and BMS being different, probably.
So, regarding hardware differences. Loosely described, the "3" pack vs. an "S" pack could be described as "
self-contained" and "
all over the place", respectively. Tesla moved all battery-related components
into the shell of the battery for Model 3. In addition to this, they massively improved cooling
(a number of parallel vanes from one side to the other, instead of one series vane going through the whole pack), completely changed how heating is done
(S/X have a resistive heater on the surface, 3/Y use the coolant loop and heat the coolant by running the motors [which are on the same coolant loop] in waste heat mode),
implied a change to the chemistry along with using a different cell size, and this is where I'll stop for now.
Besides them being managed lithium-ion battery packs with a Tesla logo on them, they have more differences than similarities. Beyond this, their stressors are different too. Model 3 packs are allowed to charge at a higher C-rate than S/X packs, and the SR+ packs especially need to deal with a higher average load due to the smaller battery. These surely have
some impact to degradation, but so do all the other differences. The net result is we
expect the 3/Y packs to last longer. But we also
observe via fleet data (various apps), that the in-car range reports fall a bit more steeply at beginning of life than S/X packs, especially for newer Model 3s. My hot take here is that they've designed a better system overall, but they're really pushing the limits of it compared to what they used to do for S/X in order to get better advertised range whereas they may have been fairly conservative before.
In summary, like everyone always expected of Tesla anyways, they took all their learnings from the S/X days and completely redesigned the system, especially tuning it for mass production.
I hope that sufficiently satiated any curiosity on differences. Hopefully that stops the relation of S/X data to a Model 3, because they really are different.
*This interpretation of the data is not necessarily accurate. We're pretty dang sure it is. But technically, only Tesla knows for certain.